Can insect data be used to infer areas of endemism? An example from the Yungas of Argentina

NAVARRO, FERNANDO; CUEZZO, FABIANA; GOLOBOFF, PABLO; SZUMIK, CLAUDIA; GROSSO, MERCEDES; QUINTANA, MARÍA G.

REVISTA CHILENA DE HISTORIA NATURAL

SOC BIOLGIA CHILE

Lugar: Asumo Santiago de Chile; Año: 2009 vol. 82 p. 507 - 522

0716-078X

The main purpose of this study is to analyze whether areas of endemism can be characterized quantitativelyby using insects, which are typically much more poorly sampled than vertebrates or plants. For this, anoptimality criterion in the search for endemic areas was used to analyze approximately 1,100 georeferencesfrom 288 species of holometabolous insects found in the study region, the Yungas (a very moist, montanerainforest), located in north-western Argentina. The optimality criterion is implemented with the programsNDM/VNDM, used to evaluate areas of endemism (i.e. a set of cells defined by two or more endemicspecies). Five grid sizes were used, three square (1°, 0.5°, and 0.25°) and two rectangular (0.25° x 0.5° and0.5° x 0.25°). In agreement with the traditional biogeographic proposal, the results of the present studyindicate that the Yungas can be characterized as a biogeographic unit with its own identity. Twenty six areasrelated to Yungas have shown 23 species of insects (in 14 families) as endemic, restricted to Yungasenvironment, and 46 species (in 10 families) as endemic, present in Yungas and surrounding habitats. Ouranalysis suggests that the use of insects to identify areas of endemism is a powerful tool, even considering thecurrent fragmentary knowledge of these groups in South America. Given that there is no criterion to choosean optimal grid size, the use of different grid sizes is crucial; medium and small sizes are highlyrecommended because both identify seemingly different patterns. The quantitative method used here is usefulto identify areas of endemism, such as disjoint areas or partially overlapping areas, which are difficult to seewith other traditional biogeographic methods.